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W. SCHAFFER Jan. l, 1929. 1 697,207

AMPLIFIER Filed Nov. 16. 1922 vmwntoz WALTER 5C HAFFER Patented Jan. l, 1929.

UNITED STATES PATENT; om=acra.

WALTER sommmn, or BERLIN, GERMALNY, nssmnon m0 GESELLSCHAFT FR DRAI-ITLOSE TELEGRAPHIE M. n. H. HALLESCHES, OF BERLIN, GERMANY, 'A con- IORATION or GEBMANY.

AMPLIFIER.

Application fi1ed November 16,.1922, Serial N0. 601,260 and in Germany November 19, 1921.

' vIn low fre 1uency an'xplifying circuit a1- rangements when itis desirecl toefl'eet large amplificatlon ancla plurality 0f tubes are,

therefore, usecl, self-oseillations are likely t0 occur in the amplifying aniangement.

. Itis an object 0f this invention 130 provid3 an arrangement in wl1ich self-oseillations are eithiar entirely preventeclor mueh clecreased.

In the clrawing, y Fig. .1 is a cliagrxinmatic 1*epresentation 0'E a circuit arrangement embodying the inventi0n and,

Fig. 2 illustrates a further embodiment of the invention.

In Fig. 1 of the acco1npanying drawing 1 is an amplifying tube whicl1 l1as an o-ut-put e. g. of 'l kW. 'Ihe anocle issuppliecl witl1 current fro1n the battery 2, and the amplified output is taken 0fi ab 3. The battery 4 supplies tl1e necessary gricl potential for the tube 1, and the small tuloe 5 is eonnect-ed in the grid circuit of the'tube 1 so asto act as a resistance.

vVhen the cu1rent t0 be amplified is transmittecl to tl1e grid of the tube 5 through the transformer 6, then alternately positive and negative otential oecurs at the gricl 0f the tube 5 Whereby the resistance 0 1 the tuloe 5 and. therefore also the otential supplied from battery 4 to the grid 0f the tube 1 are ryth1nically variecl. One of the aclvantages 0f such cireuit arrangemnt eonsists in that there are 110 transformers between tl1e tubes 5 and l, these tubes causing tl1e usual internal oscillations and singing 01 tl1e arrangements.

Furtherinore, the present cirouit arranga ment has the adVantage that the resistance variations in the tube 5 have the full effect, and there .is no output loss in tl1e controlling -tube 5, which would be unatt-ainable if traus formers were inserted between the tubes.

As is w'ellknown, it is profitable to provide in amplifying arrangements tubes connected in opposition to each other. In such opposing circuits the disturbing noises caused by heab ing or inequalities in the anode otential are balanced. Such an opposing arrangement is shown in Fig. 2, the oircuit arrangement shown in Fig. 1 being used with lt. The eur- 0f each other, ancl their primarywinclings a e connectecl in series 01 in parallel. Ob- VIOUSI V in the ax rangements shown in Figs. 1 ancl2 instead of the individual tl1bes 1 a plurality 01 such tubes may be provicled in parallel. The Same thing holds good also f01 the tubes 5.

In the same manner as they are useful for lOW frequency amplification, the circuit a1- rangements representecl in tl1e clravvings may also be employed for high frequency amplif ication. In tl1is case, instead 0f the translormers 6 ancl 3, cireuits areusecl.that are tuned 130 tl1e frequnency to be amplified.

The tubes 1 and 5 may be intereonnected in manners differing from that shown without departing from the principles of the invention, so long as the mtnner comes fairly within the scope of the appendedclaims.

Having deseribed my invention, what I claim is 1. An amplifying arrangement comprising a first amplifying tuloe having a filament, griel ancl plate, ancl a second amplifying tube having a filament, grid ancl plate, the filament 01 said second 1ne1itioned tube being C011- nected to the grid of said fi1st tube and the plate 0f saicl seconcltube beir1g connected 130 the filament of said first tube, and a source 0f potential connected between the filament o:f sa%)d first tube and the plate of said second tu e.

2. An amplifying arrangement comprising a first three electrode tuloe, a second three electrode tube, means connected between the filament andgrid of said scond tube for irnpressing thereon the electrical oscillations to be amplified, the filament and .plate of said second 'tube being, connected t0 the grid and filament respectiVely 0f said first mer'1tioned tube Whereby the amplified oseillatio'ns are impressed upon 'sail first mentioned tube and further amplified thereby, and a source of otential connected between the filament of said first tube and the plate of saidk second. tube.

3. An amplifying arrangement comprising a first set ofamplifying tubes connectecl in 

